PRACH Root Sequence Allocation for Extended Cell Range
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Solution Overview
Problem
Conventional PRACH technologies increase computational complexity and processing delays by using a large number of root sequences and detection window sizes for all UEs within a cell, regardless of their location, which limits the cell range of a gNB.
Innovation Solution
A distance-based PRACH root sequence allocation system divides root sequences into groups based on UE distance from the gNB, using different detection window sizes for each group to reduce computational load while increasing cell range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a large number of root sequences and cyclic shifts are used to generate 64 PRACH preambles for all UEs within cell range, then the cell range can be increased, but the computational complexity and processing delays of the gNB increase proportionally
Solution Approach 1:
The patent segments the set of root sequences into multiple groups, where each group is allocated to a specific detection window size. Instead of using all root sequences for all detection window sizes, the system divides them such that smaller detection window sizes use fewer root sequences while larger detection window sizes use more root sequences. This segmentation resolves the contradiction by allowing the system to scale computational resources according to the actual cell range requirements of different UEs, rather than uniformly allocating resources for the maximum cell range across all UEs.
Solution Approach 2:
The patent applies local quality by allocating different numbers of root sequences to different detection window sizes based on local requirements. Specifically, UEs with smaller detection window sizes (corresponding to shorter cell ranges) are allocated fewer root sequences, while UEs with larger detection window sizes (corresponding to longer cell ranges) are allocated more root sequences. This local optimization ensures that computational complexity is proportional to the actual cell range needed by each UE group, rather than using the maximum possible root sequences for all UEs uniformly.
2Length of stationary object
If the detection window size is increased to extend cell range, then more root sequences are required to generate all 64 preambles, but this increases computational load and processing delays
Solution Approach 1:
The patent implements dynamics by making the allocation of root sequences adaptive to the detection window size. Rather than using a fixed number of root sequences for all detection window sizes, the system dynamically allocates root sequences based on the specific detection window size being used. This dynamic allocation allows the system to optimize the balance between detection window size and processing speed, ensuring that larger detection window sizes (which extend cell range) are paired with proportionally larger root sequence allocations, rather than uniformly using maximum resources for all cases.
3Adaptability or versatility
If more root sequences are allocated to maintain 64 preambles across all detection window sizes, then preamble availability is ensured, but computational load on gNB increases
Solution Approach 1:
The patent applies parameter changes by varying the number of root sequences allocated to different detection window sizes. Instead of maintaining a constant number of root sequences (which would ensure preamble availability for all cases but increase computational load), the system changes the root sequence allocation parameter based on the detection window size. This allows the system to maintain adequate preamble availability for each detection window size while optimizing computational load by using fewer root sequences for smaller detection window sizes.
Data Source
AI summary
Distance-based physical random-access channel (PRACH) root sequence allocation to facilitate cell range improvement is presented herein. A system determines a cell range of a wireless access point; divides root sequences into respective groups of root sequences, and divides such groups of root sequences between a first group of user equipments that are located within the cell range and a second group of user equipments that are located outside of the cell range; determines a first detection window size for the first group of user equipments, and a second detection window size for the second group of user equipments—the second detection window size being greater than the first detection window size to facilitate an increase of the cell range; and receives, from a user equipment via the second detection window size and the second group of root sequences, a PRACH-based communication to facilitate the increase of the cell range.